Wetlands once covered large areas of New Zealand. Now they are some of our rarest and most at-risk ecosystems. Wetlands contain a diverse range of plants and animals and are home to many rare and threatened species. Find out more about wetlands, what lives in them and what we can do to help protect them.
Wetlands are permanently or temporarily wet areas that support plants and animals specially adapted to wet conditions.
The types of plants and animals found in wetlands depends on:
- the water, for example, the amount, depth, permanence, temperature and the chemicals found in it
- its source, for example, groundwater, surface water or rainwater.
Freshwater wetlands in the Waikato include:
- low nutrient peat domes
- moderately fertile wetlands (with kahikatea, manuka, or sedges)
- fertile raupo and harakeke (flax) swamps.
Wetlands are important storage areas for floodwaters. Think of a wetland as a giant sponge. Wetland plants slow the flow of water off the land, soaking up excess floodwater, and then slowly releasing it to maintain summer water flows.
Wetlands also act like ‘kidneys’ by filtering and cleaning the water that flows through them. Wetland plants trap sediment suspended in water, improving water quality. In riparian areas, their roots hold riverbank soil together, reducing erosion. Bacteria living in wetland soils absorb and break down nitrogen from farm run-off and leaching, improving water quality.
Healthy peat wetlands are important sinks for excess carbon, implicated in potential global warming. Find out more about how the drainage of peat releases large amounts of carbon dioxide (CO2).
Get your class to think about what other functions wetlands might perform. Ideas could include:
- recreational activities, such as fishing, hunting, photography or birdwatching
- a place where historical artifacts, such as plant fossils are preserved in the peat
- a nursery for fish, insects and nesting birds.
Wetlands come in many shapes and sizes. They range from ponds, swamps, bogs and slushy areas in paddocks to lagoons, estuaries, ditches and water races. The water they contain can be fresh, brackish, or salty.
Drainage and cultivation have greatly improved our ability to farm land profitably in the Waikato region. But it has also caused the loss of 75 percent of our region’s wetlands. We must maintain our remaining wetlands to protect their biodiversity and maintain the services that wetlands provide (for example, flood management and improving water quality).
Wetlands are often in areas that are very desirable for farming. Many wetlands have been drained and turned into pasture. Draining of peat bogs makes them shrink and stops peat formation.
About 90 percent of New Zealand’s freshwater wetlands have been destroyed in the last 150 years. Only about 30,000 hectares of wetlands are left in the Waikato from an estimated 110,000 hectares in the 1840s. This means that about three quarters of the original wetland areas have gone. Find out about the change in area of major wetlands in the Waikato region.
Find out more about continuing threats to wetlands.
- Protecting wetlands is something that you can become involved in on your own property.
- Fence off wetland areas to prevent stock from grazing and trampling.
- Carry out pest control for possums, weasels, hedgehogs, ferrets, feral cats and rats. These animals will remove birds eggs and eat the chicks and sometimes adults.
- Plant natives in the wetland area.
- Weed out the weeds so that the native plants can thrive! Weeds can overwhelm new plantings.
- Put a bell on your cat so that birds will be alerted to its presence.
- Only hunt in designated areas and times so that only target species are gathered. No native species other than pukeko can be hunted.
- Ensure that dogs are well trained to respond to you.
- Contact your local Fish and Game Council who play an important role in looking after these areas. In Hamilton you can contact them on 849 1666.
The following experiential activities encourage students to imagine that they are wetland inhabitants.
Migration at Miranda: Migration Matters
Miranda in the Firth of Thames provides wintering grounds for many migratory birds travelling south from breeding grounds as far away as Siberia and Alaska (about 10,000 to 15,000 kilometres). They travel south to avoid the harsh winter conditions.
Thirty nine of the 214 shore birds recognised world-wide have visited Miranda. The birds start to arrive in late September and leave in March-April. However, each year a few birds, such as godwits and eastern curlew, stay on.
For this activity you will need:
- hoops, enough for one for every two students
- open space the size of a netball court.
- Divide the hoops in half and place on the ground at each end of the playing space, so that there is a clear patch in the middle. At one end the hoops will represent the wintering grounds for the birds, the other end their nesting or summer grounds.
- Discuss with students the reasons why wetland habitats are being lost. For example, you could talk about the impacts of drainage, drought, fire, pollution and contamination of water, urban expansion, conversion to farmland, illegal hunting and diseases.
- Students will then represent the thousands of water birds that migrate back and forth across the playing area as the teacher signals.
- The hoops represent wetlands that can only hold two birds (people) at a time. If the birds cannot find a place to land then they must die. They must move off to the sideline.
- The students on the sideline can then call a disaster that might lead to another loss of wetland and therefore the removal of another hoop, for example, an area is drained for an urban housing development.
- Some of the dead birds can then become hunters or diseases that might result in loss of bird life.
- As the story progresses and there are more on the sideline than migrating birds, students on the sideline can join in the migration by thinking of suitable conservation activities that might result in the saving of a wetland. For example, they could think about replanting boggy areas, fencing wetlands, purchasing wetlands as reserves, regulation of hunting to particular areas, and restoration of wetlands.
- Conclude the story when you think the issues have been explored.
- Gather the group together and discuss what the activity demonstrated.
- Ask students to discuss their feelings and thoughts about the experience.
- Discuss the links to loss of habitat and loss on animal life.
- Discuss ideas related to endangered birds.
- Discuss the concepts explored in relation to a local wetland area.
- Talk about the importance of wetland areas to migrating birds.
This activity links to the Environmental Education Guidelines through:
- awareness and sensitivity about wetlands and the birds that live there
- knowledge and understanding of migratory birds and their reliance on wetlands
- exploring attitudes and values that reflect feelings of concern for the environment.
For more information about Miranda phone the Miranda Naturalists Trust on 09 232 2781 or write to the Secretary, Box 90 180, Auckland Mail Centre.
Waikato wetlands are home to 11 animal and 13 threatened plant species. Notable birdlife includes the Australasian bittern, North Island fernbird, marsh and spotless crakes, endemic shoveler and grey teal. Find out more about wetland plants and animals.
- On a tile or wooden floor (the size of the floor area will be determined by the number of groups and the number of students in each group), drop 100 squares of paper, 1cm x 1cm, of several different colours.
- The different colours represent the various juvenile species (for example, inanga and eel) that use the wetlands/ estuaries for protection and feeding grounds until they are old enough to move into their adult habitat.
- The students are the predators of these juvenile organisms. The students can use their fingers or forceps to remove the ‘juveniles’ (squares of paper) from the wetland.
- Allow the students to pick up ‘juveniles’ ONE AT A TIME for 30 seconds.
- Count the number of organisms remaining in the wetland.
- Cover the same area of the floor used above with a piece of deep-pile or shag carpet that has at least one of the colours of the paper used. This will represent the real wetlands with the plants that provide shelter and camouflage for the juvenile organisms.
- Repeat the same procedure with the squares and predator activity.
- The number of ‘juveniles’ surviving this time should increase since the ‘plants’ provide protection from the predators and they are not as easily spotted.
• What did the wooden floor represent?
• Why were more ‘juveniles’ left in the wetland carpet than the wetland floor?
• If you were a wetland animal which habitat would you like to live in? Why?
• What does a real wetland habitat look like that provides good shelter and food?
• What would the wooden floor look like as a wetland? Draw your ideas.
• Discuss other ways that wetland areas can be protected.